Different Width and Tightening System: Emergency Tourniquets on Distal Limb Segments.

Background: Tourniquets are used on distal limb segments. We examined calf and forearm use of four thigh-effective, commercial tourniquets with different widths and tightening systems: 3.8 cm windlass Combat Application Tourniquet® (CAT, combattourrniquet.com) and Special Operations Forces® Tactical Tourniquet-Wide (SOFTTW, www.tacmedsolutions.com), 3.8 cm ratchet Ratcheting Medical Tourniquet - Pediatric (RMT-P, www.ratchetingbuckles. com), and 10.4 cm elastic Stretch-Wrap-And-Tuck Tourniquet® (SWATT, www.swattourniquet.com).

Methods: From Doppler-indicated occlusion, windlass completion was the next securing opportunity; ratchet completion was one additional tooth advance; elastic completion was end tucked under a wrap.

Results: All applications on the 16 recipients achieved occlusion. Circumferences were calf 38.1±2.5 cm and forearm 25.1±3.0 cm (p<.0001, t-test, mean±SD). Pressures at Occlusion, Completion, and 120-seconds after Completion differed within each design (p<.05, one-way ANOVA; calf: CAT 382±100, 510±108, 424±92 mmHg; SOFTT-W 381±81, 457±103, 407±88 mmHg; RMT-P 295±35, 350±38, 301±30 mmHg; SWATT 212±46, 294±59, 287±57 mmHg; forearm: CAT 301±100, 352±112, 310±98 mmHg; SOFTT-W 321±70, 397±102, 346±91 mmHg; RMT-P 237±48, 284±60, 256±51 mmHg; SWATT 181±34, 308±70, 302±70 mmHg). Comparing designs, pressures at each event differed (p<.05, one-way ANOVA), and the elastic design had the least pressure decrease over time (p<.05, one-way ANOVA). Occlusion losses differed among designs on the calf (p<.05, χ²; calf: CAT 1, SOFTT-W 5, RMT-P 1, SWATT 0; forearm: CAT 0, SOFTT-W 1, RMT-P 2, SWATT 0).

Conclusions: All four designs can be effective on distal limb segments, the SWATT doing so with the lowest pressures and least pressure losses over time. The pressure change from Occlusion to Completion varies by tourniquet tightening system and can involve a pressure decrease with the windlass tightening systems. Pressure losses occur in as little as 120 seconds following Completion and so can loss of Occlusion. This is especially true for nonelastic strap tourniquet designs.